Long Term Evolution (LTE) is a framework for packet-based real-time and non-real-time services, and is proposed as the next framework used by the telecommunications industry. LTE provides many other advantages over the existing frameworks, such as more efficient use of radio spectrum. One aspect of the LTE framework is an Evolved Packet Core (EPC), an all-IP core, specified by the 3rd Generation Partnership Project (3GPP). The EPC provides mobile core functionality that, in previous mobile generations (2G, 3G), was realized through two separate sub-domains: circuit-switched for voice traffic and packet-switched for data. Using an EPC, a single all-IP domain is used.
The EPC has various components, including a Serving Gateway (SGW), a Packet Data Network Gateway (PGW), a Mobility Management Entity (MME), and a Policy and Charging Rules Function (PCRF). The PCRF is a concatenation of Policy Decision Functions and Charging Rules Functions. It supports service data flow detection, policy enforcement, and flow-based charging.
In at least one implementation there are actually several PCRFs, in the form of blades. A Diameter Proxy Agent on the same platform as the PCRFs receives Diameter messages from wireless devices that wish to establish a service through the EPC. The Diameter Proxy Agent selects the most suitable PCRF on the platform, and thereafter allows communication between the selected PCRF and the wireless device by passing Diameter messages back and forth. Such communication manages the IP address assigned to the wireless device, authorizes communication from the wireless device, manages policy associated with the wireless device, and provides accounting services (e.g. usage statistics) associated with the wireless device.
Wireline services, such as wireline telephone services but also including internet and television services, are typically implemented using a different type of server, referred to as an Authentication, Authorization and Accounting (AAA) server. An AAA server provides similar functionality as the server used in establishing wireless services. A wireline device communicates with a DSLAM or router, which then communicates with the AAA server to provide the same services as outlined above for a wireless connection. The DSLAM or router communicates with the AAA server using Radius messages.
Different divisions within a communication company frequently provide different services to its customers, some divisions providing wireless services, such as mobile communications, and some divisions providing wireline services such as landline communications, television services, and internet access. These different services may even be provided by different companies within the same family of companies. This complicates management of these services by a central authority within the main company, and requires a degree of repetition of hardware and personnel. A communications company wishing to provide its customers with a variety of services usually has to use two servers, a server compliant with the 3GPP specifications in order to receive Diameter messages and an AAA server capable of processing Radius messages, and these servers are often managed by different divisions or sub-companies. A communication company may even use more than one AAA server for a given area, as AAA servers are typically not very scalable.
A solution which allowed communication with a PCRF server using messages in the Radius format would allow a provider of both wireless and wireline services to use a single server. In addition, use by a service provider of a PCRF server rather than a dedicated wireline server allows the number of users to scale more easily, allowing simpler addition of a large number of customers.